This invention relates to an ion chamber for detecting the quantity of radiation transmitted to X-ray film. More particularly, it relates to a simplified ion chamber for X-ray detection which is composed of few components and can be produced at reduced cost.
There are currently available ion chambers for X-ray detection which employ double emitters. Such an ion chamber is disclosed in U. S. Pat. No. 4,230,944. There are also available ion chambers with a single emitter. However, these require the use of additional components and hand cutting of parts. These ion chambers do not compensate for changes in the thickness of the part resulting in artifacts and X-ray attenuation due to sharp edges. Collection area contact is also not eliminated increasing the risk of electrical leakage.
The improved ion chamber of this invention greatly reduces artifacts by the elimination of density compensating "patches" employed in the prior art units where portions of the spacer have been removed such as to provide an open pathway for the conductive paths on the collector electrode. Further, separate photoelectron barriers and sharp changes in attenuation at the chamber collection volume edge are also substantially reduced.